On the true extrema of Young’s modulus in hexagonal materials

摘要

In a paper, which has been recently published in Applied Mathematics and Computations, Khan and Ahmad (2012) [1] deal with the detection of the extrema of Young’s modulus, E, in hexagonal materials.A few issues presented in that paper, which deserve being outlined and thoroughly discussed, are tackled.Moreover, in the case of hexagonal materials, a suitable classification is suggested, an exhaustive panoramic view of the possible shape of the surface E(n) generated by Young’s modulus for all possible orientations n is illustrated, and some meaningful numerical examples are proposed.